Seoul, South Korea (CNN) -- The body of a missing sailor was recovered in the wreckage of a South Korean ship that went down in the Yellow Sea in March, Yonhap news agency reported Saturday.

The ship sank mysteriously in an incident that heightened tensions between North and South Korea.

South Korea is investigating what caused the ship to sink and has not ruled out a theory that North Korea was involved, but Seoul has avoided directly blaming North Korea, which denied allegations it was responsible.

South Korea's Yonhap reported Saturday that authorities have lifted the remaining half of the vessel, which could help aid the investigation.

The 1,200-ton patrol ship Cheonan sank near the western sea border with North Korea on March 26.

Forty of Cheonan's 104 crewmembers have now been confirmed dead, and six more are also believed dead, though they are still listed as missing.